1. Field of the Invention
It is preferred that said magnetic field providing means comprise a permanent magnet. Alternatively, said magnetic field providing means may comprise an electromagnet.
2. Description of Related Arts; and
It is preferred that each magnetic field providing means be disc shaped and be mounted within a hole. It is further preferred that:
It is preferred that any voids in each hole be filled with a filling material.
It is preferred that the heat conductivity of said housing, said magnetic field providing means, said plates and said filling material be substantially equal.
It is preferred that said housing consist of aluminium, said magnetic field providing means be rare earth magnets or bi-metal magnets, said filling material consist of an epoxy resin optionally containing metallic oxides and said plate consist of mild steel. It is further preferred that said magnetic holding device, or a portion thereof, be anodised to increase resistance to wear or corrosion.
It is preferred that said attachment surface be smooth and flat across each of said magnetic regions.
It is preferred that said magnetic regions be distributed substantially uniformly across the attachment surface. Alternatively, said magnetic regions may be uniformly distributed across one portion of the attachment surface, and distributed in higher and/or lower concentrations across other portions of said attachment surface.